Sailfish print speeds on Replicator 2

[Björn Syse]

Hi,

I've installed Sailfish 7.3 on my Replicator 2, and have some questions about print speed.

I printed the calibration cube first at 160 mm/s and then at 200 and 220 mm/s without any problems at all.

So I started using 200 mm/s as my new default speed, but have since on slightly taller models than the cube noticed that something shifts, making layers on the print to shift massivly, as if the print was sliding on the build plate (but it isn't). 

Slowed down to 160 mm/s with the same problem, but finally managed to print the piece perfectly at 140 mm/s. 

Is this some kind of limit for how fast the machine can go before it slips? or should I tighten something?

What are your print speeds with Sailfish on the Rep2?

Regards

- Björn

[Adrian Fan]

Hi, just curious. Did you set your speed under the Print-O-Matics?

Can I know what are your values under "Speed" tab in Skeinforge settings?

[Björn Syse]

Oh yeah, I'm not using Skeinforge, I'm usinge Makerware slicer.

Speed has two values - Print speed and Travel speed. I've tried setting travel speed slightly higher than print speed.

--
Björn Syse
Syse Industriell Design
http://www.syse.se
+46 706281244

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[Eighty]

Holy Cow, fella.  Slow it down!  Your bot really can't do more than about 140 mm/s reliably.

 

You printed the calibration cube successfully because the extruder never moved "far" enough to accelerate to full speed.  When you get into bigger pieces, you'll find that speeds above 120 mm/s cause issues.

 

For example, I sliced a little clip at 120 mm/s.  Started printing it, and decided to use the onboard menu to speed it up a little.  Went to 120% (which is 144 mm/s), and got an axis shift.  This can probably be minimized by adjusting your "jerk" values in the onboard preferences.  But 120 is really the limit for other reasons - your printer has to start thinking about double-stepping at that point.  And your extruder probably won't be able to maintain the temperature if you're putting out that much plastic.

 

So in my humble opinion, based on my adventurous testing, keep it to 120 mm/s (feed) and 150 mm/s (travel). 

[Björn Syse]

Oops, thanks for the tip! 

I'll keep to those values from now on. :D

[Dan Newman]

On 12 Mar 2013 , at 6:01 AM, Björn Syse wrote:

> Hi,
>
> I've installed Sailfish 7.3 on my Replicator 2, and have some questions
> about print speed.
>
> I printed the calibration cube first at 160 mm/s and then at 200 and 220
> mm/s without any problems at all.

That poor little extruder cannot really sustain those speeds reliably.
I suspect this worked because on that tiny cube things never really hit
those speeds. Had you printed a cylinder or cone with 0% infill, you might have had
a very different experience.

> So I started using 200 mm/s as my new default speed, but have since on
> slightly taller models than the cube noticed that something shifts, making
> layers on the print to shift massivly, as if the print was sliding on the
> build plate (but it isn't).

Too much mass moving around in a Rep 2 (or Rep 1 or Rep 2X) for that matter.
In the very least, you need to tune the acceleration parameters some to get
that working well.

> Slowed down to 160 mm/s with the same problem, but finally managed to print
> the piece perfectly at 140 mm/s.
>
> Is this some kind of limit for how fast the machine can go before it slips?
> or should I tighten something?

Some people successfully use 200 mm/s for travel speed. However, I recommend
against even that and suggest keeping travel around 150 mm/s. And, while
I've printed some medium size pieces at 140 mm/s on my Rep 2, I can see a very
visible quality difference between it and 120 mm/s. Issue being vibration
in the build platform and very slight shiftings of the acrylic build plate.
The latter is easily overcome by snugging the plate in better with better
support cushions below it and or using a slightlty thicker piece of glass.
As to the vibration issues, that's much harder to control without slowing
things down. (Bottlework's Rep 1 arm upgrade does make a difference on my
Rep 1, but I've not tried pushing the extrusion speeds above 120 mm/s on
it.)

Dan